Injectable polymer

Concentration effects, i.e., the dependences of Vr on injected polymer concentration (Ci), represent a further complicating factor in the quantitative... 

Each of the four columns was packed with CPG00120C d = 13.0 nm). The column dimensions and experimental conditions are listed in Table 23.1. The flow rates (solution and solvent) were set to be proportional to the cross section of the column, whenever possible. The number of drops collected in each test tube was almost proportional to the cross section, especially for the initial fractions that might show a shift in M. Figure 23.9 shows chromatograms for some the fractions separated using 2.1-, 3.9-, and 7.8-mm i.d. columns. The result with the 7.8-mm i.d. column is a reproduction of Fig. 23.2 (3). Chromatograms of the fractions obtained from the 1.0-mm i.d. column overlapped with the chromatogram of the injected polymer sample (not shown). 

Aluminum (III) citrate and sodium aluminate have been used as crosslinkers. The polymer and crosslinker solutions are injected as alternate slugs. A layer of adsorbed polymer is built up which is then crosslinked to subsequently injected polymer (200). 

A screen with 100 U.S. mesh (149 micrometer) openings was placed at the bottom of the test column to prevent the production of coarse sand particles from the test column. To avoid injection fluid turbulence disturbing the test sand, a 7.5g layer of 20-40 U.S. mesh sand was placed on top of the test sand. All fluids except polymer solutions were filtered prior to injection. Polymer solutions were injected at 5 psia and immediately followed by aqueous fluid at 40 psig. Effluent fluids were collected and filtered through 0.45 micron paper to collect the produced fine particles. 

Revell PA et al (2007) Tissue engineered intervertebral disc repair in the pig using injectable polymers. J Mater Sci Mater Med 18(2) 303-308... 

Proprietary methods are developed which inject chemical detergent solutions into the oil reservoirs to increase the viscosity of the remaining oil reservoirs. After the chemical detergent solutions are injected, polymer thickened water is provided behind the chemical detergent to drive the oil towards producing wells. 

Y. Yang and Q. Pei, Electron injection polymer for polymer light-emitting diodes, J. Appl. Phys., 77 4807-4809, 1995. 

Polymer currency with different colors for the different denominations using dyed injected polymers... 

Osmotic effects play an important role mainly at high injected polymer concentrations. They may selectively affect the retention volumes of smaller polymer species contained in the polymer sample [97], Osmotic effects within porous column packings form the basis of interesting preparative liquid chromatographic method developed by Teraoka and coworkers [98-101] and denoted the high osmotic pressure liquid chromatography. 

The concentration dependences of Vr may inverse their direction. Retention volumes may rapidly increase with decreasing Cj in the area of very low injected polymer concentrations, below the critical concentration, c, that is, when the crowding of macromolecules in solution starts to disappear. 

Goren found asymptotic behaviour, which is higher for this heterogeneous drag reduction than for a premixed homogeneous solution, whereas Tullis, Ramu, and Maus reported only little influence of the concentration of the injected polymer solution on this asymptotic value. Walters and McComb (1982) found no such influence. 

In his experiments with centrally injected polymer solutions, Bewersdorff (1984) showed in flow visualization experiments that the injected polymer solution formed a liquid thread which remained intact down the entire length of the pipe (1/d = 270), provided that the concentration of the injected polymer solution exceeded 0.3%. This polymer thread is deformed by turbulent flow, i.e., it can undergo elongation by stretching and even from loops (see Fig. 4). 

Bewersdorff HW (1982) Effect of centrally injected polymer thread on drag in pipe flow Rheol Acta 21 587... 

Films are either coextruded [12] or printed on the back of a very transparent material. The binder of these screen inks or gravure inks has to have a high melting point or crosslinking to form an elastic film to avoid being replaced by the hot injected polymer. It is also possible to coat the backside of the film with an adhesion promoter, which prevents direct contact between the printed area and the polymer. This coating can also improve the adhesion between the film and the injection-molded part [13]. 

Beside overloading effects, charge interaction effects play an important role in the retention behavior of polyelectrolytes [243]. In such cases, a strong dependence of the retention data on the concentration and volume of the injected polymer sample can also be observed. This phenomenon related to inter-molecular interactions complicates quantitative evaluation of distributions from FFF retention data. Such effects can be partly suppressed by the addition of an electrolyte but investigations of polyelectrolytes are still complicated. Other sample-sample interactions can significantly change the effective size of the polymer and thus also its retention behavior [456]. Such interactions are common with biopolymers as they are very often part of their biological function. 

STRUCTURAL CONSOLIDATION. Structural consolidation of the plaster layer is necessary for protection against mechanical stresses, including seismic activity and vibrations generated by buses that bring visitors to the Valley of the Queens. The use of injectable polymers is a viable solution. The most stable polymers must be used, and it may be necessary to custom design polymers for this purpose. The integrity of the plaster layer, before, during, and after treatment must be determined and monitored by ultrasonic, piezoelectric, or photoacoustic methods. This procedure and the use of polymers for paint layer protection will require extensive controlled experimentation, especially on the physicochemical nature of the various pig-... 

Fatty acids have been used previously in the development of polymers for biomedical applications as they are considered to be inert, inexpensive and biocompatible, as well as possessing low toxicity. This review focuses on use of different fatty acids for synthesis of injectable polymers for intended use as drug carriers. 

With the use of an on-line viscometer and universal calibration, absolute MWDs can be obtained. Because both M and intrinsic viscosity are known, the Mark-Houwink coefficients a and K can be calculated for the injected polymer ... 

Several other biodegradable, biocompatible, injectable polymers are being investigated for drug delivery systems. They include polyvinyl alcohol, block copolymer of PLA-PEG, polycyanoacrylate, polyanhydrides, cellulose, alginate, collagen, gelatin, albumin, starches, dextrans, hyaluronic acid and its derivatives, and hydroxyapatite. ... 

Fig. 3 Polymeric micelle formation of PEG-PAsp/CDDP (a), and PEG-PGlu/CDDP (b), where carboxylic groups and Pt are linked through coordination bonds, c Effect of free CDDP (left hand side) and PEG-PGlu(CDDP) micelles (right hand side) on the growth of C26 colon adenocarcinoma subcutaneously transplanted in CDFl mice (n = 10). Each drug was administrated by i. v. route five times at 2 day intervals (arrow) at the dose of 4 mg/kg CDDP eq. The molecular ratio of CDDP to the block copolymer in the micelles was calculated to be 27, and the dose of the injected polymer was 6.3 mg/kg...

In the experiment using sand pack (see Figure 5.36), when the injected polymer concentration was 600 ppm, the dynamic polymer retention at the inlet was 24.5 [ig/g and retention at the exit it was 6 [Xg/g. If the curve s trend was extended to the infinite distance, then the retention was 3.31 fig/g the... 

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